{	Problem: http://codeforces.ru/problemset/problem/3/A
 	Verdict: Accepted
}
var s:String; x1,y1,x2,y2,count,i:longint; a:array[1..110] of string;
begin
readln(s);
x1:=ord(s[1])-ord('a')+1;
y1:=ord(s[2])-48;
readln(s);
x2:=ord(s[1])-ord('a')+1;
y2:=ord(s[2])-48;
count:=0;
while (x1<>x2) or (y1<>y2) do begin
while x1<x2 do begin
    if y1<y2 then begin
        inc(count);
        a[count]:='RU';
        inc(x1);
        inc(y1);
    end else
    if y1=y2 then begin
        inc(count);
        a[count]:='R';
        inc(x1);
    end else begin
        inc(count);
        a[count]:='RD';
        inc(x1);
        dec(y1);
    end;
end;
while x1=x2 do begin
    if y1<y2 then begin
        inc(count);
        a[count]:='U';
        inc(y1);
    end else
    if y1>y2 then begin
        inc(count);
        a[count]:='D';
        dec(y1);
    end else break;
end;
while x1>x2 do begin
    if y1<y2 then begin
        inc(count);
        a[count]:='LU';
        dec(x1);
        inc(y1);
    end else
    if y1=y2 then begin
        inc(count);
        a[count]:='L';
        dec(x1);
    end else begin
        inc(count);
        a[count]:='LD';
        dec(x1);
        dec(y1);
    end;
end;
end;
writeln(count);
for i:=1 to count do writeln(a[i]);
end.